ABSTRACT
Diet is considered as one of the most important modifiable factors influencing human health, but efforts to identify foods or dietary patterns associated with health outcomes often suffer from biases, confounding, and reverse causation. Applying Mendelian randomization in this context may provide evidence to strengthen causality in nutrition research. To this end, we first identified 283 genetic markers associated with dietary intake in 445,779 UK Biobank participants. We then converted these associations into direct genetic effects on food exposures by adjusting them for effects mediated via other traits. The SNPs which did not show evidence of mediation were then used for MR, assessing the association between genetically predicted food choices and other risk factors, health outcomes. We show that using all associated SNPs without omitting those which show evidence of mediation, leads to biases in downstream analyses (genetic correlations, causal inference), similar to those present in observational studies. However, MR analyses using SNPs which have only a direct effect on the exposure on food exposures provided unequivocal evidence of causal associations between specific eating patterns and obesity, blood lipid status, and several other risk factors and health outcomes.
Subject(s)
Eating , Genetic Variation , Causality , Humans , Outcome Assessment, Health Care , Risk FactorsABSTRACT
Features of the gut microbiota have been associated with several chronic diseases and longevity in preclinical models as well as in observational studies. Whether these relations underlie causal effects in humans remains to be established. We aimed to determine whether the gut microbiota influences cardiometabolic traits as well as the risk of chronic diseases and human longevity using a comprehensive 2-Sample Mendelian randomization approach. We included as exposures 10 gut-associated metabolites and pathways and 57 microbial taxa abundance. We included as outcomes nine cardiometabolic traits (fasting glucose, fasting insulin, systolic blood pressure, diastolic blood pressure, HDL cholesterol, LDL cholesterol, triglycerides, estimated glomerular filtration rate, body mass index [BMI]), eight chronic diseases previously linked with the gut microbiota in observational studies (Alzheimer's disease, depression, type 2 diabetes, non-alcoholic fatty liver disease, coronary artery disease (CAD), stroke, osteoporosis and chronic kidney disease), as well as parental lifespan and longevity. We found 7 associations with evidence of causality before and after sensitivity analyses, but not after multiple testing correction (1198 tests). Most effect sizes (4/7) were small. The two largest exposure-outcome effects were markedly attenuated towards the null upon inclusion of BMI or alcohol intake frequency in multivariable MR analyses. While finding robust genetic instruments for microbiota features is challenging hence potentially inflating type 2 errors, these results do not support a large causal impact of human gut microbita features on cardiometabolic traits, chronic diseases or longevity. These results also suggest that the previously documented associations between gut microbiota and human health outcomes may not always underly causal relations.
Subject(s)
Coronary Artery Disease , Diabetes Mellitus, Type 2 , Gastrointestinal Microbiome , Humans , Longevity/genetics , Gastrointestinal Microbiome/genetics , Mendelian Randomization Analysis , Coronary Artery Disease/genetics , Body Mass Index , Chronic Disease , Polymorphism, Single Nucleotide , Genome-Wide Association StudyABSTRACT
OBJECTIVES: This study aimed to assess long-term, health-related quality of life (HRQOL) in a young ischemic stroke cohort, and to identify factors associated with poor HRQOL. MATERIALS AND METHODS: We conducted a survey with ischemic stroke survivors in Estonia aged 18-54 years at the time of stroke, measuring HRQOL with the three-level version of the five-dimension EuroQol (EQ-5D-3L). The control group comprised the participants of the Health Behavior among Estonian Adult Population study. A tobit regression model with a backward stepwise analysis was used to identify factors associated with low EQ-5D-3L utility scores. RESULTS: In total, 352 patients with a mean follow-up time from the qualifying event of 5.7 years and 2304 controls were included. The mean EQ-5D-3L utility score in stroke survivors was significantly lower compared with that in the general population (0.71 vs. 0.87, respectively, p<0.001). However, the subgroup with excellent functional outcome had a significantly higher mean EQ-5D-3L utility score compared with non-stroke counterparts (0.91 v 0.87, respectively, p<0.001). The largest differences between stroke survivors and the general population were in the physical domains. Coronary heart disease at the index event, and higher follow-up duration, functional disability, depressive symptoms, recurrent stroke, and not being fully employed at follow-up, were independently associated with lower HRQOL. CONCLUSION: Young ischemic stroke survivors have long-term decreased HRQOL, except for those with excellent functional recovery. Our results prioritize motor rehabilitation and highlight the importance of secondary prevention, treatment of depression, and career counselling as potential ways of increasing HRQOL.
Subject(s)
Health Behavior , Ischemic Stroke/diagnosis , Patient Reported Outcome Measures , Quality of Life , Survivors/psychology , Adult , Age Factors , Aged , Case-Control Studies , Depression/psychology , Disability Evaluation , Estonia , Female , Functional Status , Health Surveys , Humans , Ischemic Stroke/physiopathology , Ischemic Stroke/psychology , Ischemic Stroke/therapy , Male , Mental Health , Middle Aged , Recovery of Function , Recurrence , Risk Factors , Stroke Rehabilitation , Time Factors , Treatment Outcome , Young AdultABSTRACT
OBJECTIVES: This study aimed to determine short- and long-term mortality, clinical determinants and causes of death in young patients with ischaemic stroke. MATERIALS AND METHODS: We performed a hospital-based study of 18- to 54-year-old consecutive patients with ischaemic stroke, who were treated in the two largest hospitals in Estonia from 2003 to 2012. All cases were reviewed by the authors. Survival data and causes of death were obtained from the Estonian Population Registry and the Causes of Death Registry, respectively. Logistic regression and Cox proportional hazard models with backwards stepwise analysis were used to identify determinants of mortality. RESULTS: We identified 738 patients, of whom 124 died during the 5-year follow-up. Cumulative mortality rates at 30 days and 5 years were 4.5% (95% confidence interval [CI], 3.0%-6.0%) and 16.8% (95% CI, 14.1%-19.5%), respectively. The proportion of deaths due to vascular causes was 87.9% at 1 month and 54.6% at 5 years. Thirty-day mortality was independently associated with severe stroke, with a National Institutes of Health Stroke Scale (NIHSS) score >15, and post-stroke infections. The determinants of 5-year mortality were post-stroke infections, structural cardiac diseases and moderate stroke severity with NIHSS score of 7-15. CONCLUSION: The mortality rate among young patients with ischaemic stroke in Estonia is higher than that reported in previous studies and is associated with increased stroke severity, post-stroke infections and structural cardiac diseases. These results emphasize the need for more effective preventive strategies in these patient groups.
Subject(s)
Brain Ischemia/epidemiology , Heart Diseases/epidemiology , Mortality , Registries/statistics & numerical data , Stroke/epidemiology , Adolescent , Adult , Age Factors , Aged , Comorbidity , Estonia , Female , Humans , Male , Middle AgedABSTRACT
BACKGROUND: There is lack of data on the incidence of Parkinson's disease (PD) based on repeat studies. Mortality rates of PD in Estonia have never been studied before. OBJECTIVES: To estimate the incidence and mortality rates of PD in -Estonia, to compare current incidence rates with those of the prior epidemiological study in Estonia, and to examine the reported causes of death of the study population. METHODS: Eligible subjects were identified from multiple case-finding sources. Subjects were subsequently tracked on the Electronic-Health Record until either the end of the study, or their death. Incidence rates and standardized mortality ratios (SMR) were calculated. Causes of death were identified, based on the data from death certificates. RESULTS: In the current study, the overall age-adjusted incidence rate was 28.0/100,000 person-years (95% CI 25.2-30.8). Compared with the previous study, the age-adjusted incidence rate inEstonia has not significantly changed (rate ratio 1.11; p = 0.19). Overall SMR for the inception cohort of PD cases with a median follow-up time of 5 years was 1.12 (95% CI 0.88-1.36; p = 0.3). For those deceased subjects known to have had clinically diagnosed PD, this was mentioned on 46.8% of death certificates. CONCLUSIONS: Over the last 20 years, the overall incidence of PD in Estonia has remained comparatively stable. The data did not show an excess mortality in PD patients (vs. general population) in the first 5 years of the disease.
Subject(s)
Parkinson Disease/mortality , Parkinson Disease/psychology , Aged , Aged, 80 and over , Estonia/epidemiology , Female , Humans , Incidence , Male , Middle Aged , Mortality/trends , Parkinson Disease/diagnosisABSTRACT
Objective: Although abundant new information has emerged in the last decade(s) on the management of women with epilepsy (WWE), whether said knowledge has reached clinical practice remains largely unknown. We assessed knowledge of this matter among primary care and specialist doctors in Estonia. Methods: This study was conducted via an online questionnaire, which was used to explore healthcare specialists' awareness in five domains: pre-pregnancy counseling, contraception, side effects of antiseizure medications (ASMs), and the management of epilepsy during pregnancy and in the peri- and postpartum periods. Results: The survey response rate was low - 8.14%. Knowledge of epilepsy management in WWE was inconsistent among different medical specialists. The median numbers of correctly answered questions among gynecologists, neurologists, and general practitioners were 7, 6.5, and 3 of 10, respectively. Gynecologists were more informed about appropriate contraceptive methods. Neurologists were more familiar with ASM side effects. General practitioners' knowledge level for this topic was low. Surprisingly, only 30.8% of general practitioners were aware of the high teratogenic potential of valproate. Conclusions: We observed significant knowledge gaps regarding the optimal treatment of WWE of reproductive age. To improve epilepsy management, doctors' awareness of treatment considerations for this patient group needs to be increased.
ABSTRACT
Biological age (BA), a measure of functional capacity and prognostic of health outcomes that discriminates between individuals of the same chronological age (chronAge), has been estimated using a variety of biomarkers. Previous comparative studies have mainly used epigenetic models (clocks), we use ~1000 participants to compare fifteen omics ageing clocks, with correlations of 0.21-0.97 with chronAge, even with substantial sub-setting of biomarkers. These clocks track common aspects of ageing with 95% of the variance in chronAge being shared among clocks. The difference between BA and chronAge - omics clock age acceleration (OCAA) - often associates with health measures. One year's OCAA typically has the same effect on risk factors/10-year disease incidence as 0.09/0.25 years of chronAge. Epigenetic and IgG glycomics clocks appeared to track generalised ageing while others capture specific risks. We conclude BA is measurable and prognostic and that future work should prioritise health outcomes over chronAge.
Subject(s)
Aging , Epigenesis, Genetic , Aging/genetics , Biological Clocks , Biomarkers , DNA Methylation , Epigenomics , HumansABSTRACT
Background: Observational studies have linked adiposity and especially abdominal adiposity to liver fat accumulation and non-alcoholic fatty liver disease. These traits are also associated with type 2 diabetes and coronary artery disease but the causal factor(s) underlying these associations remain unexplored. Methods: We used a multivariable Mendelian randomization study design to determine whether body mass index and waist circumference were causally associated with non-alcoholic fatty liver disease using publicly available genome-wide association study summary statistics of the UK Biobank (n = 461,460) and of non-alcoholic fatty liver disease (8434 cases and 770,180 control). A multivariable Mendelian randomization study design was also used to determine the respective causal contributions of waist circumference and liver fat (n = 32,858) to type 2 diabetes and coronary artery disease. Results: Using multivariable Mendelian randomization we show that waist circumference increase non-alcoholic fatty liver disease risk even when accounting for body mass index (odd ratio per 1-standard deviation increase = 2.35 95% CI = 1.31-4.22, p = 4.2e-03), but body mass index does not increase non-alcoholic fatty liver disease risk when accounting for waist circumference (0.86 95% CI = 0.54-1.38, p = 5.4e-01). In multivariable Mendelian randomization analyses accounting for liver fat, waist circumference remains strongly associated with both type 2 diabetes (3.27 95% CI = 2.89-3.69, p = 3.8e-80) and coronary artery disease (1.66 95% CI = 1.54-1.8, p = 3.4e-37). Conclusions: These results identify waist circumference as a strong, independent, and causal contributor to non-alcoholic fatty liver disease, type 2 diabetes and coronary artery disease, thereby highlighting the importance of assessing body fat distribution for the prediction and prevention of cardiometabolic diseases.
ABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is a complex disease associated with premature mortality. Its diagnosis is challenging, and the identification of biomarkers causally influenced by NAFLD may be clinically useful. We aimed at identifying blood metabolites causally impacted by NAFLD using two-sample Mendelian randomization (MR) with validation in a population-based biobank. Our instrument for genetically predicted NAFLD included all independent genetic variants from a recent genome-wide association study. The outcomes included 123 blood metabolites from 24,925 individuals. After correction for multiple testing, a positive effect of NAFLD on plasma tyrosine levels but not on other metabolites was identified. This association was consistent across MR methods and was robust to outliers and pleiotropy. In observational analyses performed in the Estonian Biobank (10,809 individuals including 359 patients with NAFLD), after multivariable adjustment, tyrosine levels were positively associated with the presence of NAFLD (odds ratio per 1 SD increment = 1.23 [95% confidence interval = 1.12-1.36], p = 2.19 × 10-5). In a small proof-of-concept study on bariatric surgery patients, blood tyrosine levels were higher in patients with NAFLD than without. This study revealed a potentially causal effect of NAFLD on blood tyrosine levels, suggesting it may represent a new biomarker of NAFLD.
ABSTRACT
Nutrition plays an important role in the development and progress of several health conditions, but the exact mechanism is often still unclear. Blood metabolites are likely candidates to be mediating these relationships, as their levels are strongly dependent on the frequency of consumption of several foods/drinks. Understanding the causal effect of food on metabolites is thus of extreme importance. To establish these effects, we utilized two-sample Mendelian randomization using the genetic variants associated with dietary traits as instrumental variables. The estimates of single-nucleotide polymorphisms' effects on exposures were obtained from a recent genome-wide association study (GWAS) of 25 individual and 15 principal-component dietary traits, whereas the ones for outcomes were obtained from a GWAS of 123 blood metabolites measured by nuclear magnetic resonance spectroscopy. We identified 413 potentially causal links between food and metabolites, replicating previous findings, such as the association between increased oily fish consumption and higher DHA, and highlighting several novel associations. Most of the associations were related to very-low-density, intermediate-density (IDL), and low-density lipoproteins (LDL). For example, we found that constituents of IDL particles and large LDL particles were raised by coffee and alcohol while lowered by an overall healthier diet and fruit consumption. Our findings provide a strong base of evidence for planning future RCTs aimed at understanding the role of diet in determining blood metabolite levels.
ABSTRACT
Non-alcoholic fatty liver disease (NAFLD) is a complex disease linked to several chronic diseases. We aimed at identifying genetic variants associated with NAFLD and evaluating their functional consequences. We performed a genome-wide meta-analysis of 4 cohorts of electronic health record-documented NAFLD in participants of European ancestry (8,434 cases and 770,180 controls). We identify 5 potential susceptibility loci for NAFLD (located at or near GCKR, TR1B1, MAU2/TM6SF2, APOE, and PNPLA3). We also report a potentially causal effect of lower LPL expression in adipose tissue on NAFLD susceptibility and an effect of the FTO genotype on NAFLD. Positive genetic correlations between NAFLD and cardiometabolic diseases and risk factors such as body fat accumulation/distribution, lipoprotein-lipid levels, insulin resistance, and coronary artery disease and negative genetic correlations with parental lifespan, socio-economic status, and acetoacetate levels are observed. This large GWAS meta-analysis reveals insights into the genetic architecture of NAFLD.
Subject(s)
Electronic Health Records , Genetic Predisposition to Disease , Genome-Wide Association Study , Non-alcoholic Fatty Liver Disease/genetics , Genetic Variation , Humans , Linkage Disequilibrium/genetics , Lipoprotein Lipase/genetics , Obesity/genetics , PhenotypeABSTRACT
OBJECTIVE: To conduct a comprehensive analysis of circulating metabolites and incident stroke in large prospective population-based settings. METHODS: We investigated the association of metabolites with risk of stroke in seven prospective cohort studies including 1,791 incident stroke events among 38,797 participants in whom circulating metabolites were measured by Nuclear Magnetic Resonance (1H-NMR) technology. The relationship between metabolites and stroke was assessed using Cox proportional hazards regression models. The analyses were performed considering all incident stroke events and ischemic and hemorrhagic events separately. RESULTS: The analyses revealed ten significant metabolite associations. Amino acid histidine (hazard ratio (HR) per standard deviation (SD) = 0.90, 95% confidence interval (CI): 0.85, 0.94; P = 4.45×10-5), glycolysis-related metabolite pyruvate (HR per SD = 1.09, 95% CI: 1.04, 1.14; P = 7.45×10-4), acute phase reaction marker glycoprotein acetyls (HR per SD = 1.09, 95% CI: 1.03, 1.15; P = 1.27×10-3), cholesterol in high-density lipoprotein (HDL) 2 and several other lipoprotein particles were associated with risk of stroke. When focusing on incident ischemic stroke, a significant association was observed with phenylalanine (HR per SD = 1.12, 95% CI: 1.05, 1.19; P = 4.13×10-4) and total and free cholesterol in large HDL particles. CONCLUSIONS: We found association of amino acids, glycolysis-related metabolites, acute phase reaction markers, and several lipoprotein subfractions with the risk of stroke. These findings support the potential of metabolomics to provide new insights into the metabolic changes preceding stroke.
ABSTRACT
BACKGROUND: Food neophobia is considered a behavioral trait closely linked to adverse eating patterns and reduced dietary quality, which have been associated with increased risk of obesity and noncommunicable diseases. OBJECTIVES: In a cross-sectional and prospective study, we examined how food neophobia is associated with dietary quality, health-related biomarkers, and disease outcome incidence in Finnish and Estonian adult populations. METHODS: The study was conducted based on subsamples of the Finnish DIetary, Lifestyle, and Genetic determinants of Obesity and Metabolic syndrome (DILGOM) cohort (n = 2982; age range: 25-74 y) and the Estonian Biobank cohort (n = 1109; age range: 18-83 y). The level of food neophobia was assessed using the Food Neophobia Scale, dietary quality was evaluated using the Baltic Sea Diet Score (BSDS), and biomarker profiles were determined using an NMR metabolomics platform. Disease outcome information was gathered from national health registries. Follow-up data on the NMR-based metabolomic profiles and disease outcomes were available in both populations. RESULTS: Food neophobia associated significantly (adjusted P < 0.05) with health-related biomarkers [e.g., ω-3 (n-3) fatty acids, citrate, α1-acid glycoprotein, HDL, and MUFA] in the Finnish DILGOM cohort. The significant negative association between the severity of food neophobia and ω-3 fatty acids was replicated in all cross-sectional analyses in the Finnish DILGOM and Estonian Biobank cohorts. Furthermore, food neophobia was associated with reduced dietary quality (BSDS: ß: -0.03 ± 0.006; P = 8.04 × 10-5), increased fasting serum insulin (ß: 0.004 ± 0.0013; P = 5.83 × 10-3), and increased risk of type 2 diabetes during the â¼8-y follow-up (HR: 1.018 ± 0.007; P = 0.01) in the DILGOM cohort. CONCLUSIONS: In the Finnish and Estonian adult populations, food neophobia was associated with adverse alteration of health-related biomarkers and risk factors that have been associated with an increased risk of noncommunicable diseases. We also found that food neophobia associations with ω-3 fatty acids and associated metabolites are mediated through dietary quality independent of body weight.
Subject(s)
Avoidant Restrictive Food Intake Disorder , Diet , Disease Susceptibility/epidemiology , Food Preferences/psychology , Metabolic Diseases/epidemiology , Metabolomics , Adolescent , Adult , Aged , Aged, 80 and over , Cohort Studies , Cross-Sectional Studies , Estonia/epidemiology , Feeding Behavior/physiology , Finland/epidemiology , Food Quality , Humans , Metabolic Diseases/genetics , Metabolic Syndrome/epidemiology , Metabolic Syndrome/genetics , Middle Aged , Obesity/epidemiology , Obesity/genetics , Prospective Studies , Risk FactorsABSTRACT
OBJECTIVES: Levodopa is the most effective therapy for treating Parkinson's disease (PD); however, side effects such as dyskinesias and motor fluctuations may occur after some years of its usage. The aims of this study were to assess the frequency of and factors associated with motor complications among PD patients on levodopa treatment. METHODS: In a cross-sectional study carried out in 2010-2013, clinical data and treatment details were collected. Logistic regression expressed by odd ratios (OR) and 95% confidence intervals (CI) was conducted to examine the effects of several independent variables on the occurrence of motor complications. RESULTS: A total of 455 patients were enrolled, among whom 374 were on levodopa. Analysis was performed in 328 patients whose exact duration of levodopa treatment was known. Among patients included in the analysis, 25.9% experienced motor complications; of these, 21% had dyskinesias and 20.1% had motor fluctuations. Based on logistic regression, statistically significant factors associated with the occurrence of motor complications were younger age at onset of the disease, higher levodopa equivalent daily dose (LEDD), shorter time to levodopa initiation, and akinetic-rigid dominant phenotype of PD. CONCLUSIONS: This study suggests that postponing the start of levodopa therapy and maintaining low daily doses of levodopa might reduce the risk of motor complications. Our results confirm that due to higher risk of motor complications, effectively treating patients with akinetic-rigid dominant phenotype of PD might be more challenging than for patients whose dominant symptom is tremor.
Subject(s)
Dyskinesia, Drug-Induced , Levodopa , Long Term Adverse Effects , Parkinson Disease/drug therapy , Age of Onset , Aged , Antiparkinson Agents/administration & dosage , Antiparkinson Agents/adverse effects , Cross-Sectional Studies , Dose-Response Relationship, Drug , Dyskinesia, Drug-Induced/diagnosis , Dyskinesia, Drug-Induced/etiology , Dyskinesia, Drug-Induced/prevention & control , Female , Humans , Levodopa/administration & dosage , Levodopa/adverse effects , Logistic Models , Long Term Adverse Effects/chemically induced , Long Term Adverse Effects/diagnosis , Long Term Adverse Effects/prevention & control , Male , Middle Aged , Parkinson Disease/physiopathology , Time-to-Treatment , Treatment OutcomeABSTRACT
Introduction. The purpose of this study was to demonstrate the frequency and severity of nonmotor symptoms and their correlations with a wide range of demographic and clinical factors in a large cohort of patients with Parkinson's disease (PD). Methods. 268 PD patients were assessed using the validated Movement Disorders Society's Unified Parkinson's Disease Rating Scale (MDS-UPDRS), the Beck Depression Inventory (BDI), Parkinson's Disease Questionnaire (PDQ-39), the Hoehn and Yahr scale (HY), the Schwab and England Activities of Daily Living (SE-ADL) Scale, and the Minimental State Examination (MMSE). Results. Nonmotor symptoms had a strong positive relationship with depression and lower quality of life. Also, age, duration and severity of PD, cognitive impairment, daily dose, and duration of levodopa treatment correlated with the burden of nonmotor symptoms. Patients with postural instability and gait disorder (PIGD) dominance or with the presence of motor complications had higher MDS-UPDRS Part I scores expressing the load of nonmotor features, compared to participants with other disease subtypes or without motor complications. Conclusions. Though the severity of individual nonmotor symptoms was generally rated by PD patients as "mild" or less, we found a significant cumulative effect of nonmotor symptoms on patients' mood, daily activities, and quality of life.